When I lived in the Midwest, I didn’t think much about fish and seafood. The fish that came out of Lake Erie weren’t particularly appetizing. Now, that I live on the coast, fish and seafood are a regular (and tasty) part of my family’s diet. My research has convinced me that fish and seafood can be great for growing brains, preventing depression, and general health. Unfortunately, it can also be high in some pretty awful toxins. The biggest worries being mercury and PCBs.

The Toxins in Fish: Mercury and POPs

Mercury is “toxic to the fetus and children” says the American Academy of Paediatrics. Most mercury in our waters come from pollution such as burning coal or industrial or medical waste, but it can also come from gold and mercury mining and metal processing. Mercury in the environment becomes methylmercury in our waterways and oceans. Methylmercury is particularly toxic because it accumulates in muscles and other tissues. When people eat fish a fish’s lifetime of mercury can enter the person’s bodies. Larger and older fish, such as tuna, king mackeral, tilefish, swordfish, and shark tend to have the highest concentration of mercury and should largely be avoided. Many of these fish are dangerously over-fished as well.

Methylmercury goes into the organs that contain the most fats (or lipids). It is stored in measurable amounts in our tissues, including our breasts and brains. It can cross through the placenta into the fetus. Babies-to-be and young children are especially vulnerable to the effects of mercury because it can interfere with the rapidly developing brain to cause neuron degeneration and even long-term cognitive impairment.

The other toxin to worry about, PCBs, are a type of persistent organic pollutant (POP), which stays in the environment and the fatty tissue of animals and people for a long time. The biggest POP worry in fish are the industrial chemical PCBs, which have been linked to immune, reproductive, endocrine (hormone), and nervous system problems. These have been directly linked to infertility. PCBs tend to concentrate in the skin and fat of the fish and thus skinning, filleting, and cooking can reduce contamination.

Despite these contaminants, research indicates that women who eat fish during pregnancy have smarter children. Don’t avoid seafood and fish, just eat it wisely.

Wild Pacific Salmon (Chum, Coho, or Sockeye), from Alaska is the best. NEVER eat Atlantic salmon or farmed salmon, learn more below.

Salmon Warning!

Now that I live on the west coast of Canada, I’ve learned more about salmon. The most important take-away, is never eat farmed salmon. Farmed salmon is routinely contaminated with antibiotics, food dye, and in Canada and the US might be genetically engineered. It also tends to have “significantly higher” levels of organochlorine contaminants such as the POPs —PCBs and PBDEs—according to a 2004 study in the American Journal of environmental Science and Technology. Farmed salmon is one of the most antibiotic-tainted foods we can eat, because it is in their feed. Routine antibiotic exposure negatively affects the gut microbiome and reduces the efficacy of antibiotics.

Farmed salmon are naturally grey because their diet lacks the crustaceans that they eat in the wild. So they are fed pellets with artificial food dye to give them that “natural” colour artificially. There are no regulations in Canada to require retailers to label this food dye, but if you have read the Food Additives blog, then you know how I feel about artificial food dyes. (Not good: they are one of the Seven most dangerous Food Additives).

Another reason to avoid farmed salmon is that it might be genetically modified or cloned. In 2016 Health Canada ruled that genetically modified (GM) aka cloned salmon “did not pose a greater risk to human health than salmon currently available on the Canadian market.” GM salmon are designed to be sterile and grow to market size in half the time as their natural brethren. There has been tremendous outcry from consumers and wild fishery operations touting the dangers of GM salmon. The negative health effects of GM salmon include all the risks associated with all farmed salmon and they are compounded by the fact that the effects of eating cloned animal products are not well studied. There is evidence that the animals themselves are at greater risk for organ damage, tumours, and some cancers. There is considerable environmental risk as well because of the potential for the GM salmon to escape where they might further dissipate wild Salmon population. Wild populations in the Pacific are already threatened largely due to climate change and the effects of contamination from the many fish farms.

Despite this, Health Canada has determined that farmed and GM salmon don’t need to be labelled in Canada. Even the U.S. is doing a better job than us. They require that all fresh and frozen fish labels identify whether the fish is wild or farmed, if it contains artificial food colour, and from which country it originated. The manufacturers have the option of labelling whether the fish is GM or note. The EU has gone even further, they require all this to be labelled and do not allow GM salmon at all.

How do you avoid eating farmed Salmon?

Never eat anything labeled Atlantic Salmon,even Wild Atlantic Salmon, because it is farmed. There are no truly wild Atlantic Salmon fisheries in Canada as the Atlantic Salmon is an endangered species. They can call it wild because there are no regulations to stop them from doing this, despite the fact that it is obviously misleading. Most of Canada’s Atlantic Salmon is farmed in the Pacific, so its not even Atlantic in origin, just in breed.

Only buy wild, Pacific Salmon. The ideal is to find a local fisherman selling his wares from his boat or at your local farmer’s market. Since, that isn’t an option for most people you can buy from a fish vendor that takes pride in knowing his sources. Also, look for labels to back up environmental claims such as those by the Marine Stewardship Council. Learn more about reading labels for fish, and all products, in the Label Reading blog.

Learn more about healthy eating on the award-winning website TheGreenMama.com. Get great recipes, inspiration, and research (as well as lovely photographs) at your fingertips in the Green Mama books. And sign-up for the Green Mama newsletter to get a few tips delivered semi-regularly in your inbox. (I promise to never share your information, keep each email super short, and sometimes to make you laugh.) Sign-up here.

The Green Mama participates in affiliate programs, e.g. Amazon Services LLC Associates, designed to provide a means to earn $ by advertising/linking to sites such as amazon.com, without costing the buyer. I only link to products that meet green & ethical guidelines. Learn more.